Time and Distance

Velocity or Speed

The speed of something in a given direction.
Speed = (1 / timetaken)
Speed= (Distance) / (Time Taken)

Distance

At a given amount of time and with the velocity the area covered is distance.
Distance = (Speed x Time taken)

Time

The time taken usually to cover certain distance.
Time Taken = (Distance) /(Speed)

So if a and b are speed which are in ratio a:b then its time taken is (1/a) : (1/b) or b:a

km/hr to m/sec conversion:

y km/hr =y *(5 /18) m/sec.

m/sec to km/hr conversion:

y km/hr =y *(18/5) m/sec.

Suppose a man covers a certain distance at x km/hr and an equal distance at y km/hr. Then,the average speed during the whole journey is
(2 * x * y) /(x+y) km/hr.